Re-work <dialog>#show*() focus algorithm

third_party/WebKit/Source/core/css/html.css

 /*
  * The default style sheet used to render HTML.
  *
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 951 matching lines @@
     white-space: nowrap
 }
 
 /* states */
 
 :focus {
     outline: auto 5px -webkit-focus-ring-color
 }
 
 /* Read-only text fields do not show a focus ring but do still receive focus */
-html:focus, body:focus, input[readonly]:focus {
+html:focus, body:focus, dialog:focus, input[readonly]:focus {
     outline: none
 }
 
 embed:focus, iframe:focus, object:focus {
     outline: none
 }
 
 input:focus, textarea:focus, keygen:focus, select:focus {
     outline-offset: -2px
 }
@@ skipping 129 matching lines @@
     padding: 0px;
     border-width: 0px;
 }
 
 /* Allows thead sections to print at the top of each page. */
 @media print {
     thead { break-inside:avoid; }
 }
 
 /* noscript is handled internally, as it depends on settings. */